In every country, the sword use is one with magic and legend. Worshiping swords is a universal human trai because, unlike other weapons, it is not used at a distance from the target, like spears, pikes, and the like, but in single combat, man to man.
In Japan, like in Europe, unlike other weapons, swords were made on order by an artisan, and their owner gave them a soul.
Because of its cost and fragility the sword was always more worshiped than used. Warfare required mobility, and mobility required mounted archery. In this too, Japan and Europe share a tradition.

Nonetheless, because of their cost, their beauty and their value as a sign of power, blades hypnotize those who see them and those who wear them. Everyone was different, and the great ones had a name.
King Arthur had three. Excalibur, The Sword In The Stone, and Clarent.
Roland’s sword had a name. Durendal.
In “The Lord of the Rings”, Aragorn rarely mentions The Sword That Was Broken because of its power; that name itself is just a way not to mention the real name of the weapon, Narsil, which was broken in the final war against Sauron, Narsil.
Never anybody made so much fuss about a spear. These great weapons had a name because they were alive, because they had a soul, because they were like people, and they influenced the life of their owner. The same thing happened in early Japan.
Blades became important in Japan's religion. There is a special concept in Japanese, the concept of Yorishiro. A Yorishiro is an object capable of attracting spirits. And swords were obviously excellent at that. They were very good at capturing spirits. Hence their frequent presence in shrines.
A man who wants to be an emperor in Japan must have three things,and one of them is a sword, a special sword that doesn’t even look like swords look today. It’s a straight sword. We know that much even though nobody has ever seen it, nobody has ever seen it because objects of power must be hidden precisely because they have power and could be dangerous.
The curve of the blade we associate with the Japanese sword starts appearing In the 13th century with the samurai class. The tachi is first to appear. It was later replaced by the katana, which has a different purpose. The tachi is meant to be used by mounted men, the katana is optimized for a man to man fight.
But what has given to the katana much of its aura of weapon of destiny is I think the figure of the kaishakunin, the man in charge of beheading a warrior that has committed seppuku.

The delicate curve of the katana in his hands is beautiful, even in such an occasion.